#include <iostream>
using namespace std;
int main()
{
float a,b,c,d,max;
cout <<"a,b,c,d=";
cin>>a>>b>>c>>d;
if(a>max)max=a;
if(b>max)max=b;
if(c>max)max=c;
if(d>max)max=d;
cout <<"max="<<max<<endl;
return 0;	
}
